Damaged tissue, such as a lesion in a vessel, can be treated with therapeutic cells. For example, therapeutic cells can be injected into the vasculature to treat a lesion in the vessel. Some therapeutic cells will attach to the target site and provide treatment to the damaged tissue. However, depending on factors such as the dimensions of the target site, some of the therapeutic cells will flow past the lesion site without attaching to the site. Those therapeutic cells that fail to attach provide no benefit. Moreover, it has been reported that autologous bone marrow cells isolated from patients with chronic heart failure have “significantly reduced migratory and colony forming activity in vitro and a reduced neovascularization capacity in vivo” compared to cells from healthy controls (Circulation, 2004; 109: 1615-1622). The inability of such cells to migrate may lead to limited engraftment and colony forming activity may contribute to “limited therapeutic potential.”
What is needed are methods and systems for improving the engraftment of therapeutic cells at a target site or region, e.g., a region of damaged tissue.